1. Field of Invention
The present invention relates to a shelf structure, and more particularly to a shelving apparatus, wherein a plurality of post members of a foldable post can be easily assembled to rigidly support a plurality of supporting frames, and can be easily disassembled without detaching the post members.
2. Description of Related Arts
A conventional shelf structure comprises four vertical posts vertically extended from four corners of the shelf structure and a plurality of supporting panels horizontally and spacedly coupled at the vertical posts to form a shelving unit for supporting objects. As shown in FIG. 1, each vertical post comprises a plurality of tubular post members A1 arranged to align end-to-end. Each of the supporting panels comprises a panel body A2 and four tubular connectors A3 provided at four corners of the panel body A2, wherein the end of the post member A1 is inserted into the tubular connector A3 in order to connect the supporting panel at the vertical post. Accordingly, the configuration of the panel body A2 is fixed such that the size of the panel body A2 cannot be adjusted. In particular, each of the tubular connectors A3 has an upper tapered slot at an upper portion of the tubular connector A3 and a lower tapered slot at a lower portion of the tubular connector A3. Therefore, the end portions of two post members A1 are respectively inserted into the upper and lower tapered slots to securely connect the panel body A2 with the vertical posts while the vertical post are aligned end-to-end. Such tubular detachable connecting structure provides a quick assembling operation to allow the user to set up the shelving unit easily. However, after the objects are loaded and supported by the shelving unit, the overall weight of the objects will exerted to the vertical posts via the supporting panel. In other words, the end portions of two post members A1 are secured at the upper and lower tapered slots of the tubular connector A3, such that the user may require relatively larger pulling force to detach the post members A1 from the tubular connectors A3. In addition, when one of the tubular connectors A3 is broken or damaged, the supporting panels cannot be securely coupled to the vertical posts any more. In fact, in order to enhance the rigidity of the shelving unit, the structure of tubular connectors A3 must be enhanced by using rigid material such a metal or by thickening the walls of the upper and lower tapered slots of the tubular connector A3. Therefore, the material cost of the shelving unit will be substantially high and the size of the shelving unit will be enlarged. Therefore, most users will not use this conventional shelf structure in shopping centers or in the booths because the shelf structure is required to assemble and disassemble and is required to move from places to places.
An improved shelf structure is provided to enhance the storage space by reducing the size of the post connection, as shown in FIG. 2, wherein the shelf structure comprises four vertical posts each comprising a plurality of L-shaped post members B1 and a plurality of couplers B2 for coupling the post members B1 end-to-end. Each of the couplers B2 has a corresponding L-shaped coupler flange B21 and two reverse bend flanges B22 extended along two edges of the coupler flange B21, wherein a gap is formed between the reverse bend flange B22 and the coupler flange B21, such that the end portions of two post members B1 are inserted into the gap of the coupler B2 to couple the post members B1 end-to-end. In other words, two post members B1 in an abutting are secured by the coupler B2 by downwardly inserting the end portion of the upper post member B1 into the gap of the coupler B2 and by upwardly inserting the end portion of the lower post member B1 into the gap of the coupler B2. In addition, each of the couplers B2 has a detent B23 on each of the reverse bend flanges B22 to frictionally engage with the post member B1 so as to retain the coupler B2 in position. Since the cross section of the coupler B2 matches with the cross section of the post member B1, the connection between the ends of the post members B1 can be substantially reduced its size. The L-shaped detachable connecting structure provides a quick assembling operation to allow the user to set up the shelving unit easily. However, due to the frictional engagement between the end portion of the post member B1 and the coupler B2, the user may not able to correctly insert the end portion of the post member B1 into the gap of the coupler B2. It is unstable for the shelf structure when the end portion of the post member B1 cannot be fully inserted into the gap of the coupler B2. The excessive inserting force of the end portion of the post member B1 will damage the structure of the coupler B2 and will enlarge the size of the gap thereof. After the shelving unit is set up, the reverse bend flanges B22 are located at the outer surface of post member B1, such that the user may get cut or scratched by the reverse bend flanges B22 when placing the objects. Furthermore, such shaped detachable connecting structure cannot solve the same problem of how to easily disassemble the shelving unit. In other words, after the objects are loaded and supported by the shelving unit, the overall weight of the objects will exerted to the vertical posts via the couplers B2. In other words, the end portions of two post members B1 are secured at the gaps of the couplers B2, such that the user may require relatively larger pulling force to detach the post members B1 from the couplers B2. Once the gap is enlarged by the excessive detaching force, the end portions of the post members B1 cannot be securely engaged with the coupler B2 by means of frictional force. The overall structure of the shelving unit become wobble and unstable. In addition, when one of the couplers B2 is lost or damaged, the post members B1 cannot be coupled end-to-end any more.